Sure people make 6x or 4x or 1x scopes. I have always liked variable power scopes. I think the problem with 6x all the time is that you may have trouble finding something quickly with a smaller field of view.
well, the 1-6 isn't comparable to the $300-range fixed scopes. SWFA clearly states the glass is totally different (hence the 2-3x price point vs. the 10/16/20x originals).